Radioactive seed implantation treatment of prostate cancer, known as brachytherapy, is an increasingly popular and effective treatment for prostate cancer. In the brachytherapy technique, radioactive seeds are loaded into hollow needles, with the needles then being inserted into the prostate, using ultrasound imaging to guide the insertion process. The radioactive seeds are either positioned independently (not connected) within the needles and hence are located independently within the prostate after they have been moved out of the needle, or they are connected in a string arrangement by being loaded within a hollow, absorbable suture member, such as Vicryl suture.
In the suture arrangement, the individual radioactive seeds positioned therein are spaced apart, typically 1 cm. After the suture is filled with radioactive seeds, it is heated in a fixture to stiffen the suture and stabilize the position of the radioactive seeds therein. Typically, each suture arrangement has a length sufficient to accommodate at least ten radioactive seeds.
The hollow suture/radioactive seed combination was a significant improvement over the independently (unconnected, spaced seed approach, since the independent seeds, even once located in the prostate, could migrate out of the prostate to various other locations in the body, including the lungs. Migrated seeds can reduce implant quality and also potentially harm the patient.
While the hollow suture combination is a significant improvement to the independent seed arrangement, there are disadvantages to the suture combination approach. The heating step which is used to stiffen the suture combination, a necessary step in the process, can degrade the suture material. The suture combination also sometimes jams within the insertion needle, resulting in a collapsing or buckling of the suture combination. This in turn requires removal of the needle from the prostate and the subsequent reloading of the needle with independently positioned seeds. This is a time-consuming and expensive process. In addition, the commonly available ten seed per suture arrangement necessary to fit available fixtures often results in wasted radioactive seeds when seeds are required for a particular implant.
Further, the free end tips of the insertion needles must be plugged prior to the loading of the suture combination into the insertion needle, again a time-consuming process.
Hence, it is desirable to have a radioactive seed/suture arrangement which is simple, does not require a heating step, and which is more reliable in use than current suture embodiments.